The subject matter disclosed herein relates to refrigerator appliances, and more particularly to controlling the flow of a refrigerant in such a refrigerator appliance.
Many existing refrigerator appliances are based on a vapor-compression refrigeration technique. In such a refrigeration technique, a refrigerant serves as the medium that absorbs and removes heat from the space to be cooled, and transfers the heat elsewhere for expulsion. A refrigeration system that performs such a technique typically utilizes a refrigerant flow valve to control the flow of the refrigerant through the system.
Some refrigerator appliances are designed to have two separate evaporators, for example, one serving as an evaporator in a freezer compartment of the refrigerator (i.e., a freezer evaporator) and the other serving as an evaporator in a fresh food compartment of the refrigerator (i.e., a fresh food evaporator). The evaporator is the part of the refrigeration system through which the refrigerant passes to absorb and remove the heat in the compartment being cooled (e.g., freezer compartment or fresh food compartment).
In such dual evaporator refrigeration systems, the refrigerant flow valve is typically a three-way valve with one input port and two output ports, wherein the outputs are coupled to the respective evaporators. Such a three-way valve typically has only four positions to control the flow of the refrigerant through the system. The four positions include: (1) the first output port is blocked and the second output port is coupled to the input port (i.e., the first evaporator is off and the second evaporator is on); (2) the second output port is blocked and the first output port is coupled to the input port (i.e., the first evaporator is on and the second evaporator is off); (3) both output ports are open and coupled to the input port (i.e., both evaporators are on); and (4) both output ports are blocked (i.e., both evaporators are off).